1. Field of the Invention
The present invention relates to an ophthalmic measurement apparatus which measures eye refractive power distribution or wavefront aberration of a patient's eye.
2. Description of Related Art
Conventionally, there is known an apparatus which projects light in a spot shape (a measurement target) onto a fundus of a patient's eye (an examinee's eye) and detects information on wavefront of the light reflected from the fundus by using a wavefront sensor (photoelectric element) so as to measure wavefront aberration (especially, higher-order aberration) of the patient's eye (see U.S. Pat. No. 6,234,978 corresponding to Japanese Patent Application Unexamined Publication No. Hei 10-216092). In addition, there is known an ophthalmic apparatus which projects slit light onto a fundus of a patient's eye and detects the light reflected from the fundus by using a photoelectric element so as to measure the wavefront aberration or eye refractive power distribution of the patient's eye based on a signal indicating the phase difference at the time of the detection of the reflection light (see U.S. Pat. No. 5,907,388 corresponding to Japanese Patent Application Unexamined Publication No. Hei 10-108837).
Such an ophthalmic apparatus obtains information on optical characteristics (objective values) of the patient's eye based on known optical theory. However, a certain disagreement is developed between the obtained objective values and information on optical characteristics of the patient's eye which is obtained through subjective examination (subjective values). Such a disagreement is developed because the objective values are obtained based on the optical theory while the subjective values are influenced by the examinee's perception. In the case of making eye refractive power correction to prescribe spectacle lenses or contact lenses, the subjective values are obtained through the subjective examination on the basis of the objective values obtained by the ophthalmic apparatus as above or other apparatuses. Therefore, when using the objective values in preparing the spectacle lenses, data indicating values as approximate as possible to the subjective values is required in view of working efficiency.